package com.justreading.netty.websocket;

import io.netty.bootstrap.ServerBootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelOption;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.SocketChannel;
import io.netty.channel.socket.nio.NioServerSocketChannel;
import io.netty.handler.codec.http.HttpObjectAggregator;
import io.netty.handler.codec.http.HttpServerCodec;
import io.netty.handler.codec.http.websocketx.WebSocketServerProtocolHandler;
import io.netty.handler.logging.LogLevel;
import io.netty.handler.logging.LoggingHandler;
import io.netty.handler.stream.ChunkedWriteHandler;


/**
 * @author LYJ
 * @Description
 * @date 2021 年 11 月 03 日 下午7:23
 */
public class MyServer {
    public static void main(String[] args) {
        NioEventLoopGroup bossGroup = new NioEventLoopGroup();
        NioEventLoopGroup workGroup = new NioEventLoopGroup();
        try {
            ServerBootstrap bootstrap = new ServerBootstrap();
            bootstrap.group(bossGroup, workGroup)
                    .channel(NioServerSocketChannel.class)
                    .option(ChannelOption.SO_BACKLOG, 128)
                    .childOption(ChannelOption.SO_KEEPALIVE, true)
                    .handler(new LoggingHandler(LogLevel.INFO))
                    .childHandler(new ChannelInitializer<SocketChannel>() {
                        @Override
                        protected void initChannel(SocketChannel ch) throws Exception {
                            ChannelPipeline pipeline = ch.pipeline();

                            //因为基于 http 协议,使用 http 的编码和解码器
                            pipeline.addLast(new HttpServerCodec());

                            //是以块方式写,添加 ChunkedWriteHandler 处理器
                            pipeline.addLast(new ChunkedWriteHandler());

                            /*
                            说明
                                1. http 数据在传输过程中是分段, HttpObjectAggregator ,就是可以将多个段聚合
                                2. 这就就是为什么,当浏览器发送大量数据时,就会发出多次 http 请求
                            */
                            pipeline.addLast(new HttpObjectAggregator(8192));

                            /*
                                说明
                                1. 对应 websocket ,它的数据是以 帧(frame) 形式传递
                                2. 可以看到 WebSocketFrame 下面有六个子类
                                3. 浏览器请求时 ws://localhost:7000/hello 表示请求的 uri
                                4. WebSocketServerProtocolHandler 核心功能是将 http 协议升级为 ws 协议 , 保持长连接
                                5. 是通过一个 状态码 101
                            */
                            pipeline.addLast(new WebSocketServerProtocolHandler("/hello2"));

                            pipeline.addLast(new MyTextWebSocketFrameHandler());
                        }
                    });

            ChannelFuture channelFuture = bootstrap.bind(7000).sync();
            channelFuture.channel().closeFuture().sync();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            bossGroup.shutdownGracefully();
            workGroup.shutdownGracefully();
        }
    }
}
